In order to analyze the influence of foudation pit excavation on surrounding environment Based on the numerical simulation method of particle flow, the ideal particle system is constructed by boundary servo method, and the micro-mechanical parameters of rock and soil are calibrated by linear contact bond model. On this basis, the influence of foundation pit excavation on surrounding environment is analyzed. The results show that the ground deformation of 60-70m away from the foundation pit wall is about 5mm after excavation, the relative deformation of pipeline at 60-70m away from the foundation pit wall is less than 3mm, which will not cause uneven settlement of pipeline and damage; the plain filling and muddy clay around the failure foundation pit of pile wall will slide to the foundation pit, and the collapse range affects 10m approximately from the inner wall of the foundation pit, which is about 2~3 times the depth of the foundation pit. The research results can provide reference for the judgment of the stability of foundation pit wall and the deformation control of surrounding soil.